Datasheet

Section 14 IEBus™ Controller (IEB) [H8S/2258 Group]
Rev. 6.00 Mar. 18, 2010 Page 525 of 982
REJ09B0054-0600
Bit Bit Name
Initial
Value
R/W Description
7 to 4 ⎯ All 0 ⎯ Reserved
These bits are always read as 0 and cannot be modified.
3 OVE 0 R/W Overrun Control Flag
Used to control the overrun during data reception. The IEB
sets the OVE and RxE flags when the IEB receives the
next byte data while the receive data has not been read
(the RxRDY flag is not cleared) and when the parity bit
reception has been started. If this flag remains set until
acknowledge bit transfer, the IEB assumes that an overrun
error has occurred and returns a NAK to the
communications destination unit.
The communications destination unit retransmits data up to
the maximum number of transmit bytes. The IEB, however,
returns a NAK when this flag remains set because the IEB
assumes that the overrun error has not been cleared.
If this flag is cleared to 0, the IEB decides that the overrun
error has been cleared, returns an ACK, and receives the
next data.
In broadcast reception, if this flag is set during
acknowledge bit transmission, the IEB immediately enters
the wait state.
[Setting condition]
When the next byte data is received while the RxRDY flag
is not cleared and when the parity bit of the data is
received.
[Clearing condition]
When writing 0 after reading OVE = 1
2 RTME 0 R/W Timing Error
Set to 1 if data is not received at the timing specified by the
IEBus protocol during data reception. The IEB sets the RxE
flag and enters the wait state.
[Setting condition]
When a timing error occurs during data reception
[Clearing condition]
When writing 0 after reading RTME = 1